The present invention relates to a powertrain for a hybrid vehicle and a method of assembling this powertrain and a hybrid vehicle having such a powertrain.
A type of known hybrid vehicle, disclosed, in particular, in French Pat. No. 2973302, includes a transmission receiving power from a combustion engine and a hydraulic machine in order to drive the drive gears in different combinations. The transmission further includes a hydraulic pump that can recharge pressure accumulators for storing auxiliary energy in the form of hydraulic pressure, in order to then return the energy to the hydraulic machine.
Different operating modes are obtained comprising, in particular, a mode in which the vehicle is powered solely by the hydraulic machine consisting of the stopped combustion engine, without emission of polluting gas; a mode in which the vehicle is powered by the hydraulic machine and combustion engine; and a mode in which the vehicle is powered by the internal combustion engine only.
Furthermore, in a conventional manner, the combustion engine of the motor vehicles is constantly driving an alternator supplying an electric current, which feeds the on-board power supply network, and recharges the battery in this network. This constant supply of electrical current is required to ensure in particular the safety of the vehicle.
In order to provide a recharging current during shutdown of the engine with the alternator no longer rotating, which can be relatively long, in the case where the amount of stored auxiliary energy is important, the engine can be restarted to drive the generator and recharge the battery of the onboard network. However, these successive starts of the engine reduce the energy performance of the powertrain.
One can also use a technology in a known way, comprising high electrical capacitors, known as “supercapacitors,” connected to the onboard network by a power converter in order to obtain a more significant reserve of electrical energy, capable of powering this supply network during longer shutdowns of the combustion engine.
Yet these capacitors and the converter constitute a significant volume and a relatively large mass as well as high costs. In addition, electrical cables must be provided with a section sufficient to pass the high power feeding the supercapacitors, which poses problems with connecting the electrical harness.